The present invention relates in general to the placement of low viscosity material, and particularly to a collapsible ampule that is easily loaded into a syringe for dispensing the low viscosity material.
In many applications such as medical and industrial applications, and in particular dentistry, it is often desirable to dispense and accurately place a low viscosity material. Many devices have been developed, in particular within dentistry, to apply a high viscosity material such as composite filling material used to restore teeth. In these applications, cartridges containing relatively viscous material are dispensed with a syringe having a mechanical advantage. One such syringe is disclosed in U.S. Pat. No. 5,125,836 entitled xe2x80x9cEasy Loading Material Cartridge For Viscous Materialxe2x80x9d issuing to Dragan et al on Jun. 30, 1992. Therein disclosed is a syringe having a mechanical advantage used in dispensing viscous material from a cartridge. While this device discloses an apparatus for dispensing of relatively high viscosity materials, which are difficult to extrude, there is often a need to dispense low viscosity materials such as fluids and gels, in a controlled manner and dose.
Generally, low viscosity materials are applied on a surface or in a cavity. Often, dispensing of these relatively low viscosity materials, including fluids and gels, is done by brushing or dabbing with a handheld applicator. One technique for dispensing relatively small volumes of low viscosity material is by placing a quantity of the low viscosity material into a dropper type device, such as an ampule, which may be filled with the liquid or gel to be dispensed. One such device is disclosed in U.S. Pat. No. 5,320,257 entitled xe2x80x9cResilient Ampule With Articulating Linkage And Elongated Spoutxe2x80x9d issuing to Snedden on Jun. 14, 1994. Therein disclosed is an elongated ampule having a reservoir bulb on one end and an elongated spout on the other end with an articulating linkage or bellows therebetween.
Another device for dispensing a liquid medicament is disclosed in U.S. Pat. No. 5,827,233 entitled xe2x80x9cPre-filled Syringexe2x80x9d and issuing to Futikawa et al on Oct. 27, 1998. Therein disclosed is a pre-filled syringe having a flexible hollow cylinder body containing a liquid medicament inserted into the barrel.
While many of these prior devices have adequately dispensed material, they have often been difficult to use or have resulted in difficulty in removing an expended cartridge or ampule from the barrel of the syringe. Therefore, there is a need for an improved and more convenient apparatus and method for dispensing low viscosity materials easily and in a controlled manner with a single dose system.
The present invention relates to a delivery system using collapsible ampules that is easy to load and easy to remove the collapsed ampule after dispensing of a relatively low viscosity material, such as a liquid or a gel. The invention comprises a syringe having a barrel with a breech opening therein. Forward of the breech opening is a slot having a longitudinal length. The barrel is undercut forward of the breech opening under the slot to receive a substantial length of a body portion of the collapsible ampule and forms an ampule chamber. The undercut portion receives at least one half of the longitudinal length of the body portion of the collapsible ampule. The slot is sized to easily receive a nozzle portion of the collapsible ampule. Accordingly, a substantial portion of the body of the collapsible ampule securely fits within the undercut portion of the barrel and rests adjacent a forward end wall with a nozzle portion of the collapsible ampule extending there through. A rear portion of the collapsible ampule body extends into the breech opening in the barrel. In one embodiment of the syringe, a levered handle portion is utilized to aid in controlled dispensing of the material contained within the collapsible ampule. In another embodiment of the present invention, a tubular barrel is utilized having a plunger slidably moving therein. In another embodiment of the present invention, flexible fingers are used at the rear opening of the barrel of the syringe and a plunger having an intermediate reduced diameter portion is placed within the barrel. The flexible fingers retain the plunger within the barrel portion and prevent the plunger from falling out of the barrel of the syringe.
Accordingly, it is an object of the present invention to provide a syringe for dispensing a relatively low viscosity fluid or gel contained within a collapsible ampule.
It is an advantage of the present invention that control of the dispensing of low viscosity fluids is improved.
It is another advantage of the present invention that low viscosity fluids may be dispensed in a measured amount.
It is a feature of the present invention that an ampule chamber holds more than one-half of a body portion of a collapsible ampule.
It is another feature of the present invention that a slot is adapted to receive an pass through the nozzle of a collapsible ampule.
It is yet another feature of the present invention that flexible fingers extend into the bore of the barrel preventing a plunger having a reduced intermediate diameter from falling out of the barrel.
These and other objects, advantages, and features will become readily apparent in view of the following more detailed description.